The present invention relates generally to haptic feedback devices, and more particularly to vibrations and similar force sensations produced from a haptic feedback device.
An interface device can be used by a user to provide information to a computer device or an electronic device. For example, with a computer device, a user can interact with an environment displayed by the computer to perform functions and tasks on the computer, such as playing a game, experiencing a simulation or virtual reality environment, using a computer aided design system, operating a graphical user interface (GUI), or other affecting processes or images depicted on an output device of the computer. In addition, a user can interact with the electronic device, for example, using a remote control, a wireless phone, or stereo controls. Common human interface devices for such computer devices or electronic devices include, for example, a joystick, button, mouse, trackball, knob, steering wheel, stylus, tablet, and pressure-sensitive ball.
In some interface devices, force feedback or tactile feedback is also provided to the user, also known more generally herein as “haptic feedback.” These types of interface devices can provide physical sensations that are felt by the user using the controller or manipulating a physical object of the interface device. Each of these interface devices includes one or more actuators, which are connected to a controlling processor and/or computer system. Consequently, a controlling processor and/or computer system can control haptic forces produced by the haptic feedback device in coordination with actions of the user and/or events associated with a graphical or displayed environment by sending control signals or commands to the actuator(s) of the haptic feedback device.
Many low cost haptic feedback devices produce haptic forces, for example, by vibrating the manipulandum and/or the housing of the haptic feedback devices while being held by users. One or more haptic devices can be activated to provide the vibration forces. This can be accomplished, for example, by rotating an eccentric mass coupled to the shaft of each haptic device. As a result, the housing also vibrates. Two different haptic devices can be used: one haptic device having a larger mass provides low frequency rumbles and another haptic device having a smaller mass provides higher frequency vibrations.
These known haptic feedback devices, however, suffer several shortcomings. First, single-actuator systems having a relatively large rotating mass are effective at providing rough, high magnitude sensations, but are ineffective at providing subtle, high frequency vibrations, thereby severely limiting the variety of haptic feedback effects that can be experienced by a user of these haptic feedback devices. One attempted solution to this problem has been the use of a second haptic device with a smaller rotating mass. Even this attempted solution, however, is costly and uses a relatively large amount of space.
Finally, starting and stopping the rotation of the eccentric mass connected to the actuator involves time delays. These time delays, which can be as long as about 0.1 second, present a challenge in synchronizing the produced haptic forces with the events, actions or interactions in a computer simulation, game, device, etc. In addition, the delays in starting or stopping the rotation of the eccentric mass are not necessarily constant thereby presenting additional synchronization challenges.
Thus, a need exists for improved haptic feedback devices.